﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Drawing;

/// <summary>
///BarCode128 的摘要说明
/// </summary>
public class BarCode128
{
	public BarCode128()
	{
		//
		//TODO: 在此处添加构造函数逻辑
		//
	}
    //ASCII从32到127对应的条码区,由3个条、3个空、共11个单元构成,符号内含校验码
    private string[] Code128Encoding = new string[] {
"11011001100", "11001101100", "11001100110", "10010011000", "10010001100", "10001001100", "10011001000", "10011000100", "10001100100", "11001001000",
"11001000100", "11000100100", "10110011100", "10011011100", "10011001110", "10111001100", "10011101100", "10011100110", "11001110010", "11001011100",
"11001001110", "11011100100", "11001110100", "11101101110", "11101001100", "11100101100", "11100100110", "11101100100", "11100110100", "11100110010",
"11011011000", "11011000110", "11000110110", "10100011000", "10001011000", "10001000110", "10110001000", "10001101000", "10001100010", "11010001000",
"11000101000", "11000100010", "10110111000", "10110001110", "10001101110", "10111011000", "10111000110", "10001110110", "11101110110", "11010001110",
"11000101110", "11011101000", "11011100010", "11011101110", "11101011000", "11101000110", "11100010110", "11101101000", "11101100010", "11100011010",
"11101111010", "11001000010", "11110001010", "10100110000", "10100001100", "10010110000", "10010000110", "10000101100", "10000100110", "10110010000",
"10110000100", "10011010000", "10011000010", "10000110100", "10000110010", "11000010010", "11001010000", "11110111010", "11000010100", "10001111010",
"10100111100", "10010111100", "10010011110", "10111100100", "10011110100", "10011110010", "11110100100", "11110010100", "11110010010", "11011011110",
"11011110110", "11110110110", "10101111000", "10100011110", "10001011110", "10111101000", "10111100010", "11110101000", "11110100010", "10111011110",
"10111101110", "11101011110", "11110101110", "11010000100", "11010010000", "11010011100"
};
    private const string Code128Stop = "11000111010", Code128End = "11"; //固定码尾
    private enum Code128ChangeModes { CodeA = 101, CodeB = 100, CodeC = 99 }; //变更
    private enum Code128StartModes { CodeUnset = 0, CodeA = 103, CodeB = 104, CodeC = 105 };//各类编码的码头

    /// <summary>
    /// 绘制Code128码(以像素为单位)
    /// </summary>
    public int EncodeBarcode(string code, System.Drawing.Graphics g, int x, int y, int width, int height, bool showText)
    {
        if (string.IsNullOrEmpty(code)) new Exception("条码不能为空");
        List<int> encoded = CodetoEncoded(code); //1.拆分转义
        encoded.Add(CheckDigitCode128(encoded)); //2.加入校验码
        string encodestring = EncodeString(encoded); //3.编码

        if (showText) //计算文本的大小,字体占图像的1/4高
        {
            Font font = new System.Drawing.Font("宋体", height / 5F, System.Drawing.FontStyle.Regular, GraphicsUnit.Pixel, ((byte)(0)));
            SizeF size = g.MeasureString(code, font);
            height = height - (int)size.Height;
            g.DrawString(code, font, System.Drawing.Brushes.Black, x, y + height);
            int w = DrawBarCode(g, encodestring, x, y, width, height); //4.绘制
            return ((int)size.Width > w ? (int)size.Width : w);
        }
        else
            return DrawBarCode(g, encodestring, x, y, width, height); //4.绘制
    }

    //1.检测并将字符串拆分并加入码头
    private List<int> CodetoEncoded(string code)
    {
        List<int> encoded = new List<int>();
        int type = 0;//2:B类,3:C类
        for (int i = 0; code.Length > 0; i++)
        {
            int k = isNumber(code);
            if (k >= 4) //连续偶个数字可优先使用C类(其实并不定要转C类，但能用C类时条码会更短)
            {
                if (type == 0) encoded.Add((int)Code128StartModes.CodeC); //加入码头
                else if (type != 3) encoded.Add((int)(Code128ChangeModes.CodeC)); //转义
                type = 3;
                for (int j = 0; j < k; j = j + 2) //两位数字合为一个码身
                {
                    encoded.Add(Int32.Parse(code.Substring(0, 2)));
                    code = code.Substring(2);
                }
            }
            else
            {
                if ((int)code[0] < 32 || (int)code[0] > 126) throw new Exception("字符串必须是数字或字母");
                if (type == 0) encoded.Add((int)Code128StartModes.CodeB); //加入码头
                else if (type != 2) encoded.Add((int)(Code128ChangeModes.CodeB)); //转义
                type = 2;
                encoded.Add((int)code[0] - 32);//字符串转为ASCII-32
                code = code.Substring(1);
            }
        }
        return encoded;
    }
    //2.校验码
    private int CheckDigitCode128(List<int> encoded)
    {
        int check = encoded[0];
        for (int i = 1; i < encoded.Count; i++)
            check = check + (encoded[i] * i);
        return (check % 103);
    }

    //2.编码(对应Code128Encoding数组)
    private string EncodeString(List<int> encoded)
    {
        string encodedString = "";
        for (int i = 0; i < encoded.Count; i++)
        {
            encodedString += Code128Encoding[encoded[i]];
        }
        encodedString += Code128Stop + Code128End; // 加入结束码
        return encodedString;
    }

    //4.绘制条码(返回实际图像宽度)
    private int DrawBarCode(System.Drawing.Graphics g, string encodeString, int x, int y, int width, int height)
    {
        int w = width / encodeString.Length;
        for (int i = 0; i < encodeString.Length; i++)
        {
            g.FillRectangle(encodeString[i] == '0' ? System.Drawing.Brushes.White : System.Drawing.Brushes.Black, x, y, w, height);
            x += w;
        }
        return w * (encodeString.Length + 2);
    }
    //检测是否连续偶个数字,返回连续数字的长度
    private int isNumber(string code)
    {
        int k = 0;
        for (int i = 0; i < code.Length; i++)
        {
            if (char.IsNumber(code[i]))
                k++;
            else
                break;
        }
        if (k % 2 != 0) k--;
        return k;
    }

    /// <summary>
    /// 绘制Code128码到图片
    /// </summary>
    public System.Drawing.Image EncodeBarcode(string code, int width, int height, bool showText)
    {
        Bitmap image = new Bitmap(width, height);
        using (Graphics g = Graphics.FromImage(image))
        {
            g.Clear(Color.White);
            int w = EncodeBarcode(code, g, 0, 0, width, height, showText);

            Bitmap image2 = new Bitmap(w, height); //剪切多余的空白;
            using (Graphics g2 = Graphics.FromImage(image2))
            {
                g2.DrawImage(image, 0, 0);
                return image2;
            }

        }

    }
    /// <summary>
    /// 绘制Code128码到流
    /// </summary>
    public byte[] EncodeBarcodeByte(string code, int width, int height, bool showText)
    {
        System.Drawing.Image image = EncodeBarcode(code, width, height, showText);
        System.IO.MemoryStream ms = new System.IO.MemoryStream();
        image.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
        byte[] byteImage = ms.ToArray();
        ms.Close();
        image.Dispose();
        return byteImage;

    }

}
